Method for carrying out reactions of unsaturated hydrocarbons at low temperatures

ABSTRACT

METHOD FOR CARRYING OUT ALKYLATION, POLYMERIZATION OR HYDROGEN REACTIONS OF UNSATURATED HYDROCARBONS BY CONTACTING THE UNSATURATED HYDROCARBONS SUCH AS AN OLEFIN OR AROMATIC OR COMBINATION THEREOF WITH SUNGSTEN HEXAFLUORIDE AT TEMPERATURES BETWEEN 0*C. TO 50*C.

United States Patent 3,655 792" METHOD FOR CAR YING OUTREACTIONS 0F UNSATURATED HYDROCARBONS AT Low TEMPERATURES -Mauric'e M. Mitchell, In, Wallingford, Pa., Harold M. :';Fisher, Charlotte, N.C., and Edward S. Tomezsko, Media, Pa, assignors to Atlantic Richfield Company, .New York, NY. No Drawing. Original application Feb. 20, 1969, Ser. No. 801,205. Divided and this application Nov. 6, 1970,

Ser. No. 87,619 s Int.Cl.'C07c'5/24 U.S. C1. 260466 P 3 Claims ABSTRACT OF THE DISCLOSURE Method for carrying out alkylation, polymerization or hydrogenation reactions of unsaturated hydrocarbons by contacting the unsaturated hydrocarbon such as an olefin or aromatic or combination thereof with tungsten hexafluoride at temperatures between 0 C. to 50 C.

" CROSS REFERENCE TO RELATED APPLICATIONS This application is a division of our pending application Ser. No. 801,205, filed Feb. 20, 1969, entitled Method for Carrying Out Reactions of Unsaturated Hydrocarbons at Low Temperatures, now Pat. No. 3,578,650.

BACKGROUND OF THE INVENTION i Field of the invention .,,;This invention relates to a method for carrying out reactions .of unsaturated hydrocarbons, in Particular alkylation reactions, polymerization reactions and hydrogenation reactions of aromatic hydrocarbons and olefinic hydrocarbons orwith combinations thereof by contacting such hydrocarbons with tungsten hexafiuoride as the catalyst at low temperatures of the order of 0 C. to 50 C. andpreferably' from about 25 C. to 35 C.

a v I Prior art Polymerization of unsaturated hydrocarbons such as .ethylene with tungsten hexachloride to produce solid polynarily carried out at-about 60 C. on a commercial basis.

Hydrogenation of unsaturated hydrocarbons likewise is either carried out atelevated temperatures or at elevated pressures or a combination of both.

- Thepresent invention diifers from the prior art in that these reactions of unsaturated hydrocarbons can be carfried outsat .orrnearsroom temperature and at atmospheric 3,655,792 Patented Apr. 11, 1972 pressure or at pressures slightly above atmospheric pressure.

SUMMARY OF THE INVENTION In accordance with this invention there is provided a method for carrying out alkylation, polymerization and hydrogenation reactions of unsaturated hydrocarbons at low temperatures by contacting the hydrocarbons with tungsten hexafluoride.

It is an object of this invention therefore to provide a method for carrying out reactions of unsaturated hydrocarbons at low temperatures in the presence of tungsten hexafluoride.

It is another object of this invention to provide a method for alkylating aromatic hydrocarbons at low temperatures.

It is another object of this invention to provide a method for polymerizing unsaturated hydrocarbons at low temperatures.-

It is an additional object of this invention to provide a method for hydrogenating unsaturated hydrocarbons at low temperatures.

Additional objects of this invention will be apparent from the following description of the preferred embodiments and from the claims.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The unsaturated hydrocarbons to which this invention is particularly applicable include hydrocarbons having one or more olefinic double bonds in the molecule and can be straight, branched chain or cyclic and in the case of the dior polyolefins can be either conjugated or non-conjugated. The aromatic hydrocarbons to which the invention is applicable include the mononuclear aromatics such as benzene, toluene, the xylenes and higher alkylated benzenes.

It is also applicable to such compounds as tetrahyd'ronaphthalene, indene and the like. It is particularly useful for polynuclear aromatics such as naphthalene, phenanthrene, acenaphthylene and the like. The catalyst employed is tungsten hexafiuoride which can be introduced either as a gas since it is gaseous at ambient conditions of temperature and pressure or as a liquid under a small amount of pressure, i.e. about 7 to 8 pounds per square inch gauge. Tungsten hexafluoride melts at 19 C. and boils at 171 C. so that it can be used as a liquid at the low temperatures utilized for the reactions of this invention.

In carrying out alkylation reactions in accordance with this invention any of the aromatic hydrocarbons mentioned can be employed, These include benzene, toluene, the xylenes, ethylbenzene,rcumene, n propyl-benzene and other monoor polyalkyl benzenes, naphthalenesfphen anthrenes, and the like. 1

The olefins which can be utilized to 'alkyl'ate these hydrocarbons include the monoolefins rangingfrom'2 to 20 carbon atoms or more such as ethylene, propyleneybutyl enes, amylenes, hexenes, heptenes, and the like. They can be straight chain olefins such as those obtained by wax cracking or the dehydrohalogenation of chlorinated paraffins or they may be branched chain such as those obtained 3 by the polymerization of propylene. Other olefins which can be employed include the conjugated diolefins such as butadiene and isoprene or the non-conjugated diolefins such as 1,4-pentadiene, 1,5-hexadiene and the like. In addition cyclic olefins such as cyclohexene, cycloheptene, 4-methylcyclohexene and the like, can 'be employed.

The preferred method for carrying out the reaction is to introduce the catalyst into the aromatic hydrocarbon either by admixing the hydrocarbon and catalyst as liquids under moderate pressure or by adding the gaseous catalyst to the hydrocarbon until it has dissolved therein. The olefin is then added to the hydrocarbon catalyst mixture. In general, the reaction is extremely rapid even at temperatures of 25 C. to 35 C.

Under the foregoing conditions there is produced both the alkylated benzene and an olefin polymer. The relative amounts of alkylate and polymer have been found to be a function of chain length when the reaction is carried out in a hydrogen atmosphere. This is shown in the following example.

EXAMPLE I Olefin: Percent selectivity 1 Ethylene 1.0 Propylene 26.5 Butene-l 7.8

Cis-butene-Z 10.9

Trans-butene-Z 34.9

Octene-l 90 Cyclohexene 90 nroles alkylate produced 1 Percent mual moles olefin consumed X 100 It will be seen that as the chain length increases the alkylation reaction predominates.

Although a contact time of 24 hours was employed, it was noted that the reaction was extremely rapid, the olefin reacting almost as fast as it was introduced. The long time was utilized merely to insure complete reaction for purposes of determining the equilibrium.

EXAMPLE II A run was carried out similar to that in Example I using toluene and propylene except that the temperature was 25 C. Under these conditions a conversion of 39.1 percent was obtained, i.e. moles of alkylate produced per moles of olefin charged, multiplied by 100. In this product the isomer distribution was 44.0 weight percent ortho, 22.3 weight percent meta and 33.7 weight percent para.

The polymerization reaction can be carried out with monoolefins, diolefins and polyolefins having from 2 to 10 carbon atoms. In particular, olefins having from 2 to 5 carbon atoms can be polymerized readily. The polymerization reaction is carried out in much the same manner as the alkylation reaction. The olefin is introduced into the catalyst which may be either in the gaseous phase or the liquid phhse depending on the temperature and pressure.

As in the alkylation reaction the polymerization reaction is extremely rapid. EXAMPLE III Runs were carried out at 25 C. to 35 C. utilizing both argon and hydrogen as the inert atmosphere. The olefins employed were C to C In hydrogen no hydrogenation of the olefin was detected. The polymer chain length decreased with increasing molecular weight of the olefin, thus when ethylene was polymerized a chain length of approximately 1000 units was obtained Whereas with a C olefin the chain length was only about units. The chain length was the same for both cisand trans-butene- 2 polymer in the gas phase reaction.

EXAMPLE IV Runs were carried out at 25 C. to 35 C. using benzene as the solvent for the tungsten hexafluoride catalyst as in Example I, but in these runs argon was utilized as the atmosphere. In these runs the extent of alkylation and polymerization were equivalent for jtheC to C olefins. It was found that the length of the polymer chain decreased with increasing molecular weight of the olefin as in the case of the gas phase reaction.

EXAMPLE V Acenaphthylene was contacted with tungsten hexafluoride in benzene solution at 25 C. to 35 C. It was found that a polymer was formed having a molecular weight of about 6000 and a melting point in excess of 300 C. Similar results were found when carbon tetrachloride was used as the solvent for the catalyst.

EXAMPLE VI Phenanthrene was introduced into a benzene solution of tungsten hexafluoride under an argon atmosphere. In this reaction there was formed 9,10-dihydrophenanthrene. It was believed that the source of the hydrogen was from another phenanthrene molecule and that there was produced as a result dimers of phenanthrene although these could not be observed. Temperatures of 25 C. and higher were efiective for this reaction. v 1

When hydrogen was utilized as the atmosphere, increased hydrogen pressure retarded the reaction. For example, at 1 atmosphere of hydrogen pressure a yield of 46 percent of the 9,10-dihydrophenanthrene was obtained, whereas at 2.5 atmospheres of hydrogen pressure a yield of only 25 percent was obtained.

EXAMPLE VII When cyclohexene was contacted with molecular hydrogen using the tungsten hexafluoride catalyst there was produced a small amount of n-hexane togethenwith the cyclohexane. Thus in a typical run a 1 molar solution of cyclohexene in carbon tetrachloride containing a small amount of tungsten hexafluoride was rapidly converted to n-hexane in a 3 percent yield in a hydrogen atmosphere. It the reaction is allowed to proceed for more than a few minutes the n-hexane disappears and a complex product is obtained. i

EXAMPLE VIII It was found that when cyclohexene was hydrogenated utilizing a benzene solution of tungsten hexafluoride as the catalyst there was found in addition to the cyclohexane, cyclohexyl benzene. Cyclohexyl benzene was also obtained when argon was utilized as the atmosphere instead of hydrogen. There was also found in this reaction the small yield of n-hexane.

The foregoing examples demonstrate that the process of this invention can beutilized for carrying out the various reactions described for the described unsaturated hydrocarbons to give predictable products and also as shown in the examples, products which were entirely unexpected.

We claim:

1. A method for carrying out the hydrogenation of an unsaturated hydrocarbon selected from the group consisting of phenanthrene and cyclohexene which comprises contacting said unsaturated hydrocarbon with hydrogen in the presence of tungsten hexafluoride at a temperature between 0 C. and 50 C. to produce, respectively, 9,10- dihydrophenanthrene and cyclohexane as the predominant products.

2. The method according to claim 1, wherein the unsaturated hydrocarbon is a cyclohexene.

3. The method according to claim 1, wherein the unsaturated hydrocarbon is phenanthrene and the source of hydrogen is from a portion of the phenanthrene and the reaction temperature is from 25 C. to 50 C.

6 References Cited UNITED STATES PATENTS DELBERT E. GANTZ, Primary Examiner 10 V. OKEEFE, Assistant Examiner US. Cl. X.R. 

